Comparison

Fast Slow vs FastTrack

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Fast Slow

Understand your body's metabolic changes during fasting with a visual timeline. This free app guides you through different fasting zones, from digestion to deep ketosis, and offers customizable schedules and smart notifications. It provides stats, streaks, and widgets for easy progress tracking.

Highlights
  • Fasting timer with visual timeline
  • 6 customizable fasting schedules
  • 5 distinct fasting zones explained
  • Smart notifications for fasting windows
  • Stats, streaks, and trends tracking
  • Home and Lock Screen widgets
  • Siri Shortcuts integration
Features
Read full description

See what happens inside your body as you fast. Fast Slow walks you through 5 fasting zones, from digestion through fat burning to deep ketosis, so you understand what every hour of your fast is doing. 100% free. Every feature. No ads. No paywalls. No trackers. Free forever. WHAT MAKES FAST SLOW DIFFERENT Most fasting apps just count down a timer. Fast Slow shows you what's actually happening in your body at each stage: - Anabolic (0-4h): Digesting and storing nutrients - Catabolic (4-8h): Tapping into energy reserves - Fat Burning (8-12h): The metabolic switch - Ketosis (12-16h): Ketones and cellular cleanup - Deep Ketosis (16h+): Deep cellular renewal Tap any zone to learn more about the science behind it. 100% FREE. EVERY FEATURE INCLUDED. No premium tier. No trial that expires. No paywall gates. Every feature in Fast Slow is yours from day one: - All 6 fasting schedules - All stats, streaks, and trends - All widgets (Home Screen and Lock Screen) - All notifications - Siri Shortcuts - iCloud sync - Data export Everything free. No catches. FEATURES Fasting Timer One tap to start. One tap to stop. A visual timeline shows where you are, what zone you're in, and what comes next. 6 Fasting Schedules 12:12 for beginners, 14:10, 16:8 (the most popular), 18:6, 20:4, and OMAD (one meal a day) for experienced fasters. Visual Timeline Color-coded timeline of your fasting and eating windows. Plan meals, training, and recovery at a glance. Smart Notifications 7 notification types: goal reached, halfway there, one hour left, eating window alerts, and a custom last meal reminder. Nudges, not nags. Stats & Streaks Total fasts, average duration, personal records, weekly trends, and a monthly fasting calendar. Small wins add up. Widgets Home Screen and Lock Screen widgets with progress rings, timelines, and live timers. Check your fast without opening the app. Siri Shortcuts "Hey Siri, start my fast." Start, stop, and check your fasting status hands-free. AI-Powered Greetings On supported devices, Apple Intelligence creates personalized messages based on your fasting progress, streak, and time of day. iCloud Sync Your fasting data syncs automatically across all your devices. Data You Own Export your fasting history as JSON. Delete everything with one tap. Your data, your choice. DESIGNED FOR REAL LIFE Pick a schedule, adjust as needed, and let Fast Slow handle the timing. New to fasting or already have a routine, it works either way. Structure when you want it, out of the way when you don't. Built by one developer who fasts every day. No corporate agenda. No growth hacking. A well-made tool that respects your time and your data. RESPONSIBLE APPROACH Intermittent fasting can support weight management, energy, and focus, but results vary. Fast Slow provides tools and information, not medical advice. If you have health conditions, are pregnant, or have a history of eating disorders, please talk to a healthcare professional before starting. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://cernezan.com/fast-slow/privacy/

About

FastTrack

Features
Read full description

FastTrack makes intermittent fasting simple. Set your fasting window and hit start. Watch the timer count down while your body shifts into fat burn. No guesswork. No complicated setup. WHY PEOPLE LOVE FASTTRACK Track your fast Start the timer and let it run. See exactly how long is left and how far you have come. Know the moment your body stops digesting and starts burning fat. FastTrack shows each stage so you understand what is happening inside. Chat with an AI coach Got a question mid fast? Ask the built in coach any time. It answers in plain language and keeps you going when willpower runs low. Build your streak Every fast you finish adds to your streak. Watch the days stack up and turn fasting into a habit that sticks. Get a plan made for you Answer a few quick questions and FastTrack builds a schedule around your body and your goals. Go 16:8 or 18:6 or longer. You set the pace. POPULAR FASTING METHODS 16:8 18:6 20:4 OMAD Custom windows FastTrack works whether this is your first fast or your five hundredth. Download FastTrack and take control of your fasting today. Privacy Policy: https://sites.google.com/view/fasttracked/home Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Fast Slow4 screens
FastTrack4 screens

Verdict

The call

The clearest difference is update cadence: Fast Slow at every 2 weeks against FastTrack's every 2 months. FastTrack's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 18.0). On price, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Fast Slow sells 4 in-app purchases, starting at $1.99 per 7 days and FastTrack sells 3 in-app purchases, starting at $4.99 per 7 days. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Fast Slow ships an update every 2 weeks, FastTrack every 2 months. The most recent releases landed on October 24, 2026 and October 23, 2026 respectively.

Scorecard3 real differences · 7 level
Fast Slow versus FastTrack: the parameters behind the verdict, then further details
ParameterFast SlowFastTrack
PriceFreeFree
Rating5.0 (39 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings39 — better—
Update frequencyEvery 2 weeks — betterEvery 2 months
AdsNoNo
In-app purchasesYesYes
MonetizationFree—
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS18.015.0 — better
Further details — not scored
Size23 MB42 MB
Age rating4+4+
DeveloperZan CerneAbdul Manan

In-app purchases

4 purchases

Fast Slow

Subscriptions2
  • Legacy$1.997 Days
  • Legacy - Yearly3 Days trial$12.991 Year
One-time2
  • Buy Me a Coffee$2.99
  • You're Amazing$9.99
3 purchases

FastTrack

Subscriptions2
  • FastTrack Weekly$4.997 Days
  • FastTrack Pro$39.991 Year
One-time1
  • Lifetime Pro$79.99

Questions

Is Fast Slow free?
Fast Slow is free to download, with in-app purchases available.
Is FastTrack free?
FastTrack is free to download, with in-app purchases available.
Do Fast Slow or FastTrack have ads?
Neither Fast Slow nor FastTrack shows ads.
Which is updated more often, Fast Slow or FastTrack?
Fast Slow ships an update every 2 weeks, and FastTrack every 2 months. Most recently, Fast Slow was updated on October 24, 2026 and FastTrack on October 23, 2026.

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